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#A PPP FRAME INCLUDES FCS SERIAL#
#A PPP FRAME INCLUDES FCS PLUS#

The LCP also negotiates and sets up control options on the WAN data link, which are handled by the NCPs. The LCP establishes the point-to-point link. The LCP functions within the data link layer and has a role in establishing, configuring, and testing the data-link connection. PPP – Link Control Protocol (LCP) (3.2.2.2) The LCP sets up the PPP connection and its parameters, the NCPs handle higher layer protocol configurations, and the LCP terminates the PPP connection. Most of the work done by PPP is at the data link and network layers by the LCP and NCPs. PPP does not impose any restrictions regarding transmission rate other than those imposed by the particular DTE/DCE interface in use. The only absolute requirement imposed by PPP is a full-duplex circuit, either dedicated or switched, that can operate in either an asynchronous or synchronous bit-serial mode, transparent to PPP link layer frames. PPP operates across any DTE/DCE interface (RS-232-C, RS-422, RS-423, or V.35).

Synchronous serial, such as those that use basic telephone service for modem dialup connections.

Asynchronous serial, such as leased line services.

If too many errors are detected, PPP takes the link down.Īt the physical layer, you can configure PPP on a range of interfaces, including The link quality management feature, as shown in Figure 3-20, monitors the quality of the link. PPP includes many features not available in HDLC: There are many advantages to using PPP including the fact that it is not proprietary. PPP provides a standard method for transporting multiprotocol packets over point-to-point links. PPP originally emerged as an encapsulation protocol for transporting IPv4 traffic over point-to-point links. Some of the more common NCPs are Internet Protocol (IPv4) Control Protocol, IPv6 Control Protocol, AppleTalk Control Protocol, Novell IPX Control Protocol, Cisco Systems Control Protocol, SNA Control Protocol, and Compression Control Protocol. PPP allows the simultaneous use of multiple network layer protocols.

Family of Network Control Protocols (NCPs) for establishing and configuring different network layer protocols.

Extensible Link Control Protocol (LCP) for establishing, configuring, and testing the data-link connection.

HDLC-like framing for transporting multiprotocol packets over point-to-point links.

#A PPP FRAME INCLUDES FCS SERIAL#

PPP establishes a direct connection using serial cables, phone lines, trunk lines, cellular telephones, specialized radio links, or fiber-optic links. PPP encapsulates data frames for transmission over Layer 2 physical links.

#A PPP FRAME INCLUDES FCS PLUS#

O’Reilly members experience live online training, plus books, videos, and digital content from nearly 200 publishers.PPP encapsulation has been carefully designed to retain compatibility with most commonly used supporting hardware. Get Mobile Backhaul now with the O’Reilly learning platform. In the latter case, the network consumes. In IP addressing, the PPP link can be treated as an unnumbered serial interface (no IP address assigned) or then as a network. In case of mobile backhaul, IP is encapsulated into PPP by marking the protocol field accordingly, and then including data and optional padding. 2 byte FCS is the default, 4 byte FCS may be negotiated. Other values may be negotiated.įrame Check Sequence (FCS), is calculated over the entire frame. Together the information and padding may include up to 1500 octets, which is the default value for the Maximum Receive Unit (MRU). Information consists of data to be transmitted, and padding may be included. Protocol indicates the protocol carried in the information field. Control fields consists of ‘00000011’, other values may be used if so agreed. Address field is typically a broadcast field of all ‘1’s, meaning all stations.

A flag marks the start of the frame with a bit sequence ‘01111110’.